Firewire Voltage on AL Firewire

[Kynan Shook]

Nope, that's the way things are.  The specifications on Apple's 
developer website says that the 15" Ti PowerBooks have FireWire at 
12-17 V unregulated DC with no load.  The Aluminum ones say 12.8 V 
unregulated DC.  However, the Al has a much higher current capacity 
than the Ti; the Al is rated for up to 7 W *per port*, 1.5A max for the 
two ports combined.  The Ti is limited to 0.5A, and 6 W.  So you should 
be able to get more power out of the Al, you just might need to adapt 
to a lower voltage.  Of course, both of these pale in comparison to a 
desktop model; the G5 provides 25 V, 15W.

I'd guess that anything further on this subject is likely beyond the 
scope and experience of this list (unless anybody else here has any 
further information for them?); you'd probably be better off visiting 
developer.apple.com, or otherwise getting in contact with Apple; if 
necessary, perhaps even purchasing a developer "technical support 
incident" (about US$195, unless you are already an ADC Select or 
Premier member, in which case you get some as part of the membership 
fee).

"Hans-Peter Ochsner" <Hanspeter.Ochsner at sinar.ch> writes:
> We've noticed that the Voltage on the firewire-ports on the new =
> AL-Powerbooks is significant
> lesser than it was on the TI-Powerbooks. We measured that on the TIs, =
> the Voltage is around
> 16 V, with or without power-adapter plugged.
> On the new AL PowerBooks, the voltage is only around 12 V and drops 
> down =
> to 8 V, depending
> on the state of the battery and the load.
>
> Does anyone knows a "trick" (i.E. Battery, firmware-tweaking) to get a 
> =
> higher voltage?